Regulating electric-arc lamps.



R. FRIESE.

RBGULATING ELECTRIC ARC LAMPS. IAPPLIGATION FILED JULY 15, 1913.

1,097,1 75 Patented May 19, 1914.

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UNITED $TATES PATENT curios.

nornnr amass, or onaane'rrnusune, GERMANY, ASSIGNOR r SIEMENS- scnucxnza'rwnnxn, e. m. 2B. 11., or BERLIN, GER-MANY, A CORPORATION or GERMANY,

BEGULATING ELEGTR-IQ ABC LAMPS.

Specification of Letters Patent.

Patented May 19, 1914,

Appiicationfiled I 11237 15, 1913. Serial No. 779,154. 1

i To all whom it may concern Be it known that I, ROBERT Fnmsn, a sub- ]ect of the German Emperor, and resident of 'Charlot-tenburg, near Berlin, Germany, have invented certain new and useful Improvements in Regulating Electric-Arc Lamps, of 1 which the followin is a specification.

My invention re ates to a system. of regulating electric arc lamps and has for its obect more particularly to vary the intensity of light of such lamps especially for the purpose of stage illumination, which requires generally a regulation for decreasing the' intensity of .light of such lamps for dimming, darkening or similar purposes. In systems of this kind which have heretofore been in use the regulating of arc lamps has either been done by inserting resistance in series therewith, and the dimming or darkening more particularly has been accomplished by more or less shutting off the light of the lamps by means of shades, blinds, screens and similar mechanical auxiliaries. The former method of electrically regulating arc lamps for dimming or darkening purposes apparently hast-he disadvantage of not being able to produce dimness of the light below a certain light intensity, as the arc lamp will not-be able to properly operate on a current below a certain limit, this limit being generally fixed by the hissing of the arc and by other factors depending upon the size and particular construction of the lamp, the electrodes and so forth. On the other hand to produce the dimming or darkening efiect'solely by mechanical auxiliaries, such as shades, blinds, screens, and the like, results into the necessity of consuming the full operating current during theentire dimming or darkening period, which is of course expensive and in some cases even prohibitive for commercial. reasons.

In order to discard, therefore, the disadvantages of either mode of regulation and to combine the advantages of both systems I have devised a new system of regulating,

arc lamps, which will enable one to install arc lamps for stage illumination purposes,

the regulating means according to my pres ent nvention.

Referring now more particularly to the drawing, I have shown an arc lamp 10, the arc of which is surrounded by a casing 11. This casing has an opening toward one side, and said opening is plOVlC *d with a cover 12, which is hinged at the 1 "per end of the opening as shown at 13. fed by the mains 14 and 15 ,wer the switch 16 in such a way that, when; said switch is thrown into a position 3*: shown in the drawing, the full current will flow through the arc lamp, thus causing a maximum of light to be emitted therefrom. A regulating resistance .17 is connected with the switch 16 and may be inserted into the main circuit of the lamp or cut out and into circuit in a number of steps as indicated by the contact points a, b, e, (Z, and 6. Thus by mov-. ing switch 16 from contact a, over I), 0, (Z to e the current flowing through the lamp will be gradually weakened and produce a decrease of the light emitted therefrom. The regulating resistance 17 is 'so dimensioned relatively to the size and construction of the arc lamp, that if the full resistance 17 is switched into circuit, the lamp will properly operate .without trespassing the above mentioned limit, at which the current is no more suliicient to operate the arc in a proper manner. This limit I have found to lie, for instance for a lamp of 15 amperes at a value of somewhat below 6 amperes, so that at 6 or 7 amperes the proper operation of the lamp at a decreased light emission will yet be safeguarded. In order, now, to further decrease the light of the lamp beyond this limit, I make use of a mechanical auxili'ary for gradually shutting ed. the opening ofthe'lamp casing 11. r

I In the drawing I have shown an arrangement for closing the cover 12 electrically by a solenoid 18 with a. plunger 19 which is connected over thecord 20 and the rollers 21 with the cover 12 in such a manner that the weight of the plunger- 19 will tend to keep the cover 12 in its uppermost position, while if the solenoid be excited the plunger 19 will be'di'awn into he solenoid 18 and h arc lamp 1O is ment 23 is connected with the last contact 6 of said regulating resistance 17 and so positioned that, while switch 16 is being moved 'flOIII contact 6 over contacts 7", g, h and i to j, the resistance 17 will always be kept in series with the arc during regulation of the resistance 22 for the solenoid 18. Thus by moving the switch 16 through the whole range from contact a to contact j the lamp will be regulated in steps between giving its maximum lightand absolute darkness. Dur-' ing the first period 0 f regulation,.viz. between a and e the feeding current of the arc will be decreased down to a permissible value, and during the second period between 6 and j, the resistance l7vw-ill,further be kept in circuit with thearc over the contact segment 23 contacting with switch 16 and cause the lamp to, operate at a minimum current, while atthe same time the solenoid 18 will be excited by steps, thus gradually closing the cover 12 for the lamp.

In the foregoing I have shown and described only some embodiments of my invention, and I wish to be understood as not limiting myself to the exactconstructions as shown and described, since changes may be made thereon withoutdepartingfrpm the principle of my invention. i

I claim as new and desire to secure by Let I ters Patent of the United States:

1. In combination with anarclarnp, regulating means for reducing the operating current for said lannp, a device for shading said lamp and mechanism for causing said two means to operate in succession to each other.

2. In combination with, an, arc lamp, means for gradually reducing the operating current for said lamp d'ownto a permissible amount, means for gradually shutting off the light emitted by saidlamp, and switching instrume'ntalities for causing said two means to operate in succession to each other. 3. In combination with an arc lamp, 3. regulating resistance in series with the are for regulating the current of said lamp, a dimming device for said lamp vand mechanism for operating said regulating resistance and'said dimming device in succession.

4:. In combination with an arc lamp a regulating resistance in series with thefarc, a dimming device for said lamp, a controller comprising steps for including said regulating resistance and subsequent steps for operating saiddimming device i,

In witness whereof I have hereunto set my signature in. thepresence of two subscribing witnesses. 4 ROBERT FRIESE. -Witnesses:-

' HENRY HASPER, VVOLDEMAR HaUPT. 

